Re: Poulsen first light

["Ed Phillips" <evp-at-pacbell-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I actually did find an arc oscillator that operated
> at 5kv called the "collins" system, but I gather it didn't work all that
> well, since DeForest's system seemed to be the preferred one.  

	Although (Frederick Archie) Collins did write some good very early
books on "wireless" for amateurs, he was also something of a crook and
frequently in serious trouble with the law.  I may be wrong, but I seem
to remember something about a scam involving a "wireless telephone"
system which might have used (or allegedly used) something such as you
read about.  I'd be interested in that reference, by the way.

>It used a
> low voltage ( <500v ) source.  I can see why high voltage wouldn't be
> desirable after a point.  The strength of the magnetic field would control
> the pitch of the negative resistance curve, and would also control how
> wide the voltage swings could be.  Of course, as you increase voltage and
> decrease amperage in the source, you limit the magnetic fields you can
> produce, unless you use permanent magnets or electromagnets which
> *aren't* powered by the source current.  I'll probably do some experiments
> with higher voltages anyway, but thanks very much for the tip.  I do have
> some NIB's which are incredibly strong. . . (four of these quarter sized
> wonders will hold many hundreds of pounds of iron)
> 
>         --Mike

	For a description of a more conventional arc oscillator which almost
certainly did work take a look at:

 http://www.geocities-dot-com/CapeCanaveral/Hangar/6160/poulsen/

It is from the early 1920's, and includex enough construction details to
be of interest.  An arc oscillator is NOT a simple device!  As for the
magnetic field, I also have thought about using the neodynium based
magnets, but haven't ever really tried to design the magnetic circuit. 
You need a field of a thousand gauss or more over an air gap of the
order of an inch, so it will take quite a few of the permanent magnets.

	Keep us informed!

Ed